linux-kernel - [PATCH RFC] usb: gadget: Set self-powered based on MaxPower and bmAttributes

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Message-Id: <20250204105908.2255686-1-prashanth.k@oss.qualcomm.com>
Date: Tue,  4 Feb 2025 16:29:08 +0530
From: Prashanth K <prashanth.k@....qualcomm.com>
To: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Thinh Nguyen <Thinh.Nguyen@...opsys.com>,
        Peter Korsgaard <peter@...sgaard.com>,
        Sabyrzhan Tasbolatov <snovitoll@...il.com>
Cc: linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
        Prashanth K <prashanth.k@....qualcomm.com>, stable@...r.kernel.org
Subject: [PATCH RFC] usb: gadget: Set self-powered based on MaxPower and bmAttributes

Currently the USB gadget will be set as bus-powered based solely
on whether its bMaxPower is greater than 100mA, but this may miss
devices that may legitimately draw less than 100mA but still want
to report as bus-powered. Similarly during suspend & resume, USB
gadget is incorrectly marked as bus/self powered without checking
the bmAttributes field. Fix these by configuring the USB gadget
as self or bus powered based on bmAttributes, and explicitly set
it as bus-powered if it draws more than 100mA.

Cc: stable@...r.kernel.org
Fixes: 5e5caf4fa8d3 ("usb: gadget: composite: Inform controller driver of self-powered")
Signed-off-by: Prashanth K <prashanth.k@....qualcomm.com>
---
 drivers/usb/gadget/composite.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c
index bdda8c74602d..1fb28bbf6c45 100644
--- a/drivers/usb/gadget/composite.c
+++ b/drivers/usb/gadget/composite.c
@@ -1050,10 +1050,11 @@ static int set_config(struct usb_composite_dev *cdev,
 	else
 		usb_gadget_set_remote_wakeup(gadget, 0);
 done:
-	if (power <= USB_SELF_POWER_VBUS_MAX_DRAW)
-		usb_gadget_set_selfpowered(gadget);
-	else
+	if (power > USB_SELF_POWER_VBUS_MAX_DRAW ||
+	    !(c->bmAttributes & USB_CONFIG_ATT_SELFPOWER))
 		usb_gadget_clear_selfpowered(gadget);
+	else
+		usb_gadget_set_selfpowered(gadget);
 
 	usb_gadget_vbus_draw(gadget, power);
 	if (result >= 0 && cdev->delayed_status)
@@ -2615,7 +2616,9 @@ void composite_suspend(struct usb_gadget *gadget)
 
 	cdev->suspended = 1;
 
-	usb_gadget_set_selfpowered(gadget);
+	if (cdev->config->bmAttributes & USB_CONFIG_ATT_SELFPOWER)
+		usb_gadget_set_selfpowered(gadget);
+
 	usb_gadget_vbus_draw(gadget, 2);
 }
 
@@ -2649,8 +2652,11 @@ void composite_resume(struct usb_gadget *gadget)
 		else
 			maxpower = min(maxpower, 900U);
 
-		if (maxpower > USB_SELF_POWER_VBUS_MAX_DRAW)
+		if (maxpower > USB_SELF_POWER_VBUS_MAX_DRAW ||
+		    !(cdev->config->bmAttributes & USB_CONFIG_ATT_SELFPOWER))
 			usb_gadget_clear_selfpowered(gadget);
+		else
+			usb_gadget_set_selfpowered(gadget);
 
 		usb_gadget_vbus_draw(gadget, maxpower);
 	} else {
-- 
2.25.1